Simultaneous spatial and temporal regularization in low-dose dynamic contrast-enhanced CT cerebral perfusion studies.

Area of Science:

• Medical Imaging
• Radiology
• Computational Imaging

Background:

• Low-dose dynamic contrast-enhanced computed tomography (DCE-CT) is crucial for cerebral perfusion studies.
• Image reconstruction in low-dose DCE-CT requires effective regularization techniques to mitigate noise and artifacts.
• Traditional methods like Total Variation (TV) have limitations in preserving fine details and accuracy.

Purpose of the Study:

• To evaluate the performance of Total Generalized Variation (TGV) and its combination with low-rank and sparse decomposition (LTGV) for low-dose DCE-CT cerebral perfusion imaging.
• To compare TGV and LTGV against Total Variation (TV) and its combination with low-rank and sparse decomposition (LTV), as well as reconstructions without regularization.
• To quantitatively assess the impact of these regularizers on image quality and cerebral perfusion parameter (CPP) estimation accuracy using simulation and clinical data.

Main Methods:

• Simulation study using a digital brain phantom with low-dose DCE-CT image reconstruction.
• Generation of cerebral perfusion parameter (CPP) images from reconstructed DCE-CT data.
• Quantitative evaluation using Peak Signal-to-Noise Ratio (PSNR), Structural Similarity Index Measure (SSIM), linear regression analysis for CPP accuracy, and region analysis.

Main Results:

• LTV and LTGV demonstrated higher PSNR and SSIM values compared to other methods, particularly with increased regularization parameters.
• TGV generally showed the best performance in accuracy, followed by LTGV, with TV significantly differing from the other regularizers.
• Simulation and clinical results showed overall consistency, although some discrepancies arose from differences in low-dose image generation.

Conclusions:

• TGV and LTGV are effective regularizers for enhancing the accuracy of cerebral perfusion parameter estimation in low-dose DCE-CT.
• The study provides valuable insights into the performance of different regularizers, aiding in the selection of optimal methods for low-dose DCE-CT perfusion studies.
• These findings support the potential for improved diagnostic capabilities in cerebral perfusion imaging with reduced radiation exposure.